The current research examines joint collective action (e.g., between Blacks and Whites) from the perspective of disadvantaged group members, for whom such action reflects a dilemma of whether to “sleep with the enemy.” Integrating insights from research on intergroup contact, helping, and collective action, we suggest that an important part of this dilemma lies in the tension between a key motivation (joint action’s perceived instrumentality) and a key barrier (joint action’s perceived potential to normalize power relations between the groups). We test this idea in three studies using different methods and different intergroup contexts. Studies 1 and 2 showed that manipulated instrumentality increased motivation for joint action, whereas manipulated normalization decreased this motivation. Study 3 showed that manipulated normalization decreased perceptions of instrumentality and thus undermined the motivation for joint action, and this occurred mainly among high identifiers with the disadvantaged group, for whom the dilemma should be most salient. We discuss the implications of our findings for theory and research on collective action and call for future research on joint action.